Some involve
substances introduced into the body, such as alcohol, drugs, nicotine,
caffeine, salt and sugar —
substances that can be mood - altering — but
others involve a process: extreme preoccupation
with relationships, money, sex, religion, gambling, romance, violence, the arms race, television and so on.
The coffee bean which coffee comes from is one of the most complicated food
substances in the world; it contains
caffeine of course, but it's also loaded
with a truly massive variety of
other natural compounds.